"It is just that the blanket is not completely taut yet," said lead flight director Bill Reeves. "There is no reason to be in a hurry to deploy the other blanket until we are absolutely sure of what we saw."

Engineers say they are not overly concerned about the lack of tension in the wing. They say it is producing electricity - and the shuttle could leave Alpha with the wings in that state.

NASA unsure when second attempt will happen

"The current configuration on the solar arrays is good -- so there is no rush" to reach a solution, said Flight Director John Curry.

The flight directors say they are unsure when they will try to extend the wings again -- or how they might modify their procedures to try and avoid a similar problem.

The wing deployment misfire came at the tail end of an otherwise successful 7 and a half hour spacewalk by NASA astronauts Carlos Noriega and Joe Tanner.

Working closely with Canadian astronaut Marc Garneau -- at the controls of Endeavour's 50-foot robot arm -- the spacewalkers helped guide in and latch on the $600 million solar array package.

Around the space station they went -- connecting cables -- turning nuts -- wrestling wires ... always careful to stay connected to the station or the shuttle.

Cameras added to helmets

The spacewalking hard-hats showed TV viewers how they do their jobs -- like no others before them. Their helmets were outfitted with small TV cameras -- and transmitters -- they captured an astronaut's point of view of a terminally exotic job site.

Entertaining as it might have been for viewers, NASA added the cameras to the helmets so that engineers on the ground could help the spacewalkers troubleshoot any snags.

At one point, Noriega radioed down to mission control that the removal of a bolt "required minimal effort."

"Yeah, we see that," came the reply from Capsule Communicator Mario Runco.

Tanner and Noriega had a front row seat for the spectacular unfurling of the solar wing.

"Golly they are huge," remarked Tanner. When told they were two thirds deployed he asked incredulously: "you mean there is more?"

When the arrays are fully deployed -- they will span 240 feet -- from tip to tip. They are expected to generate enough power to supply the daily needs of 10 homes. Three more identical arrays are slated to be attached to the burgeoning station in the next few years.

Construction project will tax agency's resources

The same duo are scheduled to conduct two more spacewalks Tuesday and Thursday. They will continue joining cables and attaching hardware to link the solar arrays to the station power grid and they will move antennas and other hardware to make way for the arrival of the US laboratory "Destiny" -- due to arrive in Atlantis' cargo bay in January.

In addition, they will attach a device that will measure the static electricity that is generated near the huge solar arrays. NASA is concerned it might be a hazard for future spacewalkers.

Sunday's footloose foray was the eleventh spacewalk outside Alpha since its first module was launched 2 years ago.

Over the next 5-6 years, construction of the space station will heavily tax the ranks of NASA's spacewalking corps. No less than 160 station-building spacewalks are planned -- more than the cumulative total logged by US astronauts to date.

Endeavour's five man crew is slated to return to the Kennedy Space Center in Florida next Sunday.